X-band two-stage Doherty power amplifier based on pre-matched GaN-HEMTs

作者：Lee Wooseok; Lee Hwiseob; Kang Hyunuk; Lim Wonseob; Han Jaekyung; Hwang Keum Cheol; Lee Kang Yoon; Yang Youngoo^*

来源：IET Microwaves Antennas & Propagation, 2018, 12(2): 179-184.

DOI：10.1049/iet-map.2017.0127

• power amplifiers
• gallium compounds
• high electron mobility transistors
• X-band two-stage Doherty power amplifier
• prematched-HEMT
• prematched gallium-nitride high electron mobility transistors
• prematching circuits
• GaN

This study presents an X-band two-stage Doherty power amplifier (DPA) using pre-matched gallium-nitride high electron mobility transistors (GaN-HEMTs). The pre-matched GaN-HEMT includes partial matching circuits in the package using bond-wires and capacitors. To obtain broad bandwidth and low loss, the pre-matching circuits were carefully designed to have a low matching quality factor. The optimum second harmonic impedance, which was extracted from the harmonic source/load pull simulations, was applied to the pre-matching circuits for high efficiency. Using the pre-matched GaN-HEMTs, an X-band two-stage power amplifier (PA) was designed and implemented. By combining two two-stage PAs in parallel, a DPA was built. The implemented DPA exhibited a max gain of 25.5dB and an output power from 42.5 to 45.8dBm at the frequency band from 7.9 to 8.4GHz. It also showed a high efficiency of 37.8% at the 6dB back-off output power level of 39.6dBm.

• 出版日期2018-2-7